1. Field
The disclosed embodiments relate to video decoding, and more particularly relate to a method of storing motion vector information and a video decoding apparatus using the method capable of reducing memory requirement for storing motion vector information.
2. Description of the Related Art
As consumer demand for multimedia entertainment and information, as well as the desire for higher display quality have increased, requirement for processing, transmission and storage resources for video content, such as memory size and bandwidth, have also increased. A number of standards have been developed to assure the display quality of the video content while achieving considerable improvements in compression and decompression efficiency, such as the International Telecommunication Union, Telecommunication Sector (ITU-T) H.264 recommendation (hereinafter the “ITU-T H.264 standard”).
The ITU-T H.264 standard is a block-based video codec standard capable of providing an enhanced compression ratio of the video content without significantly sacrificing video quality. As for the ITU-T H.264 standard, intra-frame and inter-frame prediction are introduced to remove spatial correlations in the current picture and temporal redundancies between successive video pictures. There is an inter-frame prediction mode called Direct mode which is utilized the motion vector information of the other video pictures, so as to generate a standard compliant compressed bitstream.
Although the ITU-T H.264 standard specifies the representation of the standard compliant compressed bitstream and the method of decoding, there is some latitude for improving memory storage capacity and transmission bandwidth. For example, due to higher display quality with increasing resolutions or faster frame rates, the motion vector information of earlier video pictures retained for decoding later video pictures may unfavorably consume more storage space and transmission bandwidth, as well as degrade decoding efficiency.
Accordingly, there is a need for techniques that allow a video decoding apparatus to reduce unnecessary motion vector information according to the syntax information of the compressed bitstream.